1. Field of the Invention
The present invention relates to a high frequency multilayer integrated circuit in which a multilayer (or multi-layered) circuit board (herein, which is called multilayer board) is provided with a high frequency element and a power-supply/control element to thereby process high frequency signals.
2. Related Art
In a recent technology, according to positive usage of high frequency band area such as micro-wave band or milli-wave band, an integrated circuit (IC) technology or printed circuit board pattern formation technology have been put into practical use, and hence, an integrated circuit (IC) has been widely utilized for treating or processing high frequency signals of the micro-wave band or milli-wave band. As such integrated circuit, there is disclosed in, for example, Japanese Patent Laid-open (KOKAI) Publication No. HEI 5-299906, a high frequency multilayer integrated circuit having various circuit elements provided for a multilayer board.
FIG. 3 shows one example of a conventional high frequency multilayer integrated circuit such as disclosed in the above Japanese Patent Publication. With reference to FIG. 3, the high frequency multilayer integrated circuit 50 includes a first high frequency circuit 51 embedded in a first embedded dielectric or dielectric substance 52. Upper and lower earth electrodes 53 and 54 of the first high frequency circuit 51 are also disposed on both vertical sides of the first embedded dielectric 52, and an upper dielectric 55 is disposed on the upper earth electrode 53. Furthermore, a power-supply/control circuit connection via hole 56 is vertically arranged in a manner that a lower end thereof is connected to the first high frequency circuit 51 and an upper end thereof penetrates the upper earth electrode 53 and extends to the upper surface of the upper dielectric 55. Further, it is to be noted that the term “power-supply/control” used herein generally means “power-supply and/or control”.
A power-supply/control circuit element 57 is arranged on the surface of the upper dielectric 55 and connected to a power-supply/control circuit line or wiring 58 disposed on the same surface of the upper dielectric 55. The first embedded dielectric 52 is formed with a cavity so that an intermediate portion of the high frequency circuit 51 is exposed, and in this cavity, a high frequency circuit element 59 is arranged so as to be connected to the high frequency circuit 51.
A second embedded dielectric 60 is disposed below the lower earth electrode 54, and a second high frequency circuit 61 is also embedded in the second embedded dielectric 60. Furthermore, a lowermost earth electrode 62 is disposed on the lower surface of the second embedded dielectric 60, and the first high frequency circuit 51 and the second high frequency circuit 61 are connected to each other through a layer-connection via hole 63.
Further, it is to be noted that, in the description concerning the above conventional high frequency multilayer integrated circuit 50, the term such as “upper”, “lower” and the like are used in the state illustrated in FIG. 3.
In the high frequency multilayer integrated circuit of the structure mentioned above, the high frequency signal is inputted through, for example, a left-hand end of the first high-frequency circuit 51 disposed in the first embedded dielectric 52 and then transmitted to an input side terminal of the high frequency circuit element 59 through the layer-connection via hole 63, and the second high frequency circuit 61 disposed in the second embedded dielectric 60. Then, the high frequency signal appearing on an output side terminal of the high frequency circuit element 59 advances again toward the right-hand end of the first high frequency circuit 51. In this operation, required power-supply/control signal and so on are transmitted to the input and output side terminals of the high frequency circuit element 59 from the power-supply/control circuit element 57 through the power-supply/control circuit wiring 58 and the power-supply/control circuit connection via hole 56.
With the conventional high frequency multilayer integrated circuit mentioned above, however, the high frequency circuit and the power-supply/control circuit are disposed to the dielectric layers which are different from each other. This provides a problem of difficulty in reduction of the number of the dielectric layers. In addition, since the circuit element is arranged only on one surface, i.e., upper surface, of the multi-layered dielectric material, it is difficult to integrate it into compact size and also difficult to reduce circuit arrangement area.
Moreover, it is required to work a cavity to the dielectric, which results in increasing of a working cost, and in addition, it is necessary to take countermeasure to heat radiation from the high frequency circuit element disposed in the cavity. Such undesired phenomenon results in deterioration in performance of the high frequency circuit element due to heat generation thereof and decreasing of its usable life time, thus being undesirable.